Prior art that is related to this technical field can be found in, for example, the technical specification 3GPP TS 23.251, the technical specification 3GPP TS 44.018, the technical specification 3GPP TS 45.008, the technical specification 3GPP TS 43.003, and the technical specification 3GPP TS 45.005.
The following meanings for the abbreviations used in this specification apply:
ARFCN absolute radio frequency channel number
BA BCCH allocation
BCCH broadcast control channel
BS base station
BSC base station controller
BSIC base station identity code
GERAN GSM EDGE radio access network
GPRS General Packet Radio Service
GSM Global System for Mobile Communication
EDGE Enhanced Data Rate for GSM Evolution
eNB evolved NodeB
ePLMN equivalent PLMN
ID identification
HLR home location register
LAC location area code
LAI location area identification
LTE Long Term Evolution
LTE-A LTE Advanced
MCC mobile country code
MNC mobile network code
MOCN multiple operator core network
MSG mobile switching centre
NCC network colour code
NCL neighbour cell list
PACCH packet associated control channel
PBCCH packet broadcast control channel
PLMN public land mobile network
RNC radio network controller
SACCH slow associated control channel
SCH synchronisation channel
SGSN serving GPRS support node
SI system information
SIx system information type x message
UE user equipment
In the last few years, an increasing extension of communication networks, e.g. of wire based communication networks, such as the Integrated Services Digital Network (ISDN), DSL, or wireless communication networks, such as the cdma2000 (code division multiple access) system, cellular 3rd generation (3G) and fourth generation (4G) communication networks like the Universal Mobile Telecommunications System (UMTS), enhanced communication networks based e.g. on LTE or LTE-A, cellular 2nd generation (2G) communication networks like the Global System for Mobile communications (GSM), the General Packet Radio System (GPRS), the Enhanced Data Rates for Global Evolution (EDGE), or other wireless communication system, such as the Wireless Local Area Network (WLAN), Bluetooth or Worldwide Interoperability for Microwave Access (WiMAX), took place all over the world. Various organisations, such as the 3rd Generation Partnership Project (3GPP), Telecoms & Internet converged Services & Protocols for Advanced Networks (TISPAN), the International Telecommunication Union (ITU), 3rd Generation Partnership Project 2 (3GPP2), Internet Engineering Task Force (IETF), the IEEE (Institute of Electrical and Electronics Engineers), the WiMAX Forum and the like are working on standards for telecommunication network and access environments. Examples for new communication technologies are for example LTE and LTE-A of 3GPP.
Network sharing is a way for operators to share the heavy deployment costs for mobile networks, e.g. in the roll-out phase. In the current mobile telephony marketplace, functionality that enables various forms of network sharing is becoming more and more important.
A network sharing architecture allows different core network operators to connect to a shared radio access network. The operators do not only share the radio network elements, but may also share the radio resources themselves.
One example for such a network sharing architecture is the MOCN approach (or Full MOCN) which is applicable to different communication network types, for example GERAN. In the MOCN approach, a network-sharing configuration is provided where only the radio access network, is shared while the core networks are separated according to the sharing communication networks, such as different PLMNs.
In the MOCN approach, it is proposed to rely both on the use of a common ID for the communication network, such as a common PLMN-ID broadcast in the cells that are shared between different communication networks, and on the routing of all data and signalling to/from a given host network element (mobile station or UE) from/to the appropriate operator core network by the BSC(s) controlling these cells. Unlike Full MOCN, MOCN is defined such that it enables the use of network sharing with host network elements such as mobile stations that do not support Full MOCN and also host network elements that do support Full MOCN. In other words, MOCN allows operators to use network sharing with legacy host network elements (which do not support Full MOCN) and supporting host network elements (which do support Full MOCN) wherein these host network elements use the common PLMN ID e.g. in PLMN (re)selection procedures. It may be noted that with MOCN, a mobile station or other host network element in a cell shared by MOCN does not know whether or not this cell is shared: the list of PLMNs sharing the cell is not sent by such network on the radio interface and is thus not visible to this mobile. On the other hand, in Full MOCN, new information is transmitted on the radio interface, specifically as a minimum the list of PLMNs sharing the cell. This information can only be acquired by a mobile station or other UE that can receive and understand it, i.e. a mobile station or UE that supports Full MOCN, referred to herein as a “supporting” UE, host network element, or mobile station or the like. The supporting UE can itself select a PLMN in this list, and the network will route the registration to the indicated selected PLMN. Thus, with this terminology, MOCN works with both supporting and non-supporting UEs or other devices, whereas Full MOCN only works with supporting UEs or other devices.
However, in network sharing environments such as MOCN, a problem may arise with regard to mobility of host network elements such as UEs when multiple operators are sharing the same access network. For example, when a local communication area or cell is shared between several PLMNs it has to be ensured that mobility procedures are possible between this cell and neighbouring cells of these PLMNs.
That is, besides a PLMN (re)selection procedure, a suitable mechanism and control for mobility between shared cells and non-shared cells has to be provided.